1. Field of the Invention
This invention relates to a cordless telephone which comprises a base unit and a remote unit which communicate with each other through radio transmission. Further, the base unit and the remote unit have the same identification code (abbreviated as ID code hereafter). The ID code is transmitted when trying to call the remote unit from the base unit or trying to call the base unit from the remote unit. Communication between both units is established only when the received ID code agrees with its ID code.
2. Prior Art
In a cordless telephone of the prior art, ID code is stored in an OTP-ROM (One Time programmable ROM), a fuse P-ROM or the like. Abbreviated dialing numbers to call a destination telephone by identifying it with a number of digits less than the digits of the dialing number of the destination telephone are stored in a RAM installed in a processor circuit, which is realized by a microcomputer, or a RAM provided near the processor circuit. Consequently primary batteries or secondary batteries for the backup of the, RAM which stores the abbreviated dialing numbers, have usually been used in preparation for power outage.
As explained, the prior art system requires the RAM to store ID codes and the RAM to store abbreviated dialing numbers to be separately provided, as well as batteries to backup the RAM memory element, storing the abbreviated dialing numbers to be provided. Thus the telephone set has thus been complex in construction and high in production cost